diff --git a/Pilz.UI/PaintingControl/PaintingControl.vb b/Pilz.UI/PaintingControl/PaintingControl.vb
index e1a7890..669815f 100644
--- a/Pilz.UI/PaintingControl/PaintingControl.vb
+++ b/Pilz.UI/PaintingControl/PaintingControl.vb
@@ -129,10 +129,16 @@ Public Class PaintingControl
         Refresh()
     End Sub
 
-    Private Sub CheckKeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown, Me.KeyUp
-        pressedShift = e.Shift
-        pressedControl = e.Control
-        pressedAlt = e.Alt
+    Private Sub CheckKeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown
+        If e.Shift Then pressedShift = True
+        If e.Control Then pressedControl = True
+        If e.Alt Then pressedAlt = True
+    End Sub
+
+    Private Sub CheckKeyUp(sender As Object, e As KeyEventArgs) Handles Me.KeyUp
+        If e.Shift Then pressedShift = False
+        If e.Control Then pressedControl = False
+        If e.Alt Then pressedAlt = False
     End Sub
 
     Friend ReadOnly Property AreaSelectionRectangle As RectangleF